Charging external battery from laptop

In general, the MacBook does not provide the ability to use it as a power source to charge an external battery pack or other device through the USB-C port. The USB-C port on your MacBook is for charging the notebook itself, not for charging other devices back.

ashill wrote:

I have an external portable USB-C battery pack that I often want to charge from my MacBook when the MacBook is plugged into the wall. Is this possible? The battery pack happily charges when I plug the USB-C cable into a wall outlet, but the MacBook seems to only want to accept power from the battery; I cannot see how to convince the laptop to charge the battery. (Especially when travelling, it's most convenient to only bring one wall USB-C DC adapter and charge the laptop from the wall and the portable battery and/or iPad from the laptop.)

I've tried this using both the USB-C cable that came with an older MacBook Pro and the USB-C cable that came with my iPad. Both cables work fine charging the battery from the wall via a USB-C DC power adapter, but neither works to charge the battery from the laptop.

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Did you find an answer?

I was wondering if converting the usb-c to usb-a would prevent it from accepting power.